Extension-compasses.



BURT E. GOVE, OF WINTHR-OP, MASSACHUSETTS.

ExTENsioN-cowlPAssEs.

SPECIFICATION forming part of Letters Patent No. 714,575, dated November 25, 1902.

Application filed July 23,1902. Serial No. 116,733. (No model.)

To all whom it may concern.:

Be it known that I, BURT E. Govn, a citizen of the United States,residing at Winthrop, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Extension-Compasses, of which the following is a specification.

This inventionrelatesA to extension-compasses and contemplates the provision, in connection with a pair of Compasses having legs of equal length, of means for holding the said legs in immovable adjusted position and a particular form of socket in connection with one leg, whereby extension devices may be adjustably connected thereto and of themselves adjustable and adapted to hold a pencil or other marking device at different distances from one of the legs of the Compasses and which serves las a centering means of su pport. p l

The inven tion also contemplates the details of construction and arrangement of the several parts, which will be more fully hereinafter described and claimed.

The object of the invention is to provide a simple and eective device of a comparatively inexpensive nature and convenient in use. p

In the drawings, Figure lis a perspective view of the extension-compasses embodying the features of the invention and shown arranged for use. Fig. 2 is a rear elevation of the compasses proper without the extension attachments. Fig. 3 is an edge elevation of the upper portion of the Compasses proper. Fig. 4 is a detail perspective view of a segmental head-plate forming a part of the compasses proper. Fig. 5 is a detail perspective view of a connecting-sleeve for the extension devices.

Similar numerals of reference are employed to indicate corresponding parts in the several views.

The "numerals 1 audf2, respectively, designate the legs of the Compasses proper, having lower pointedterminals 3 and the usual form of joint 4`at their upper ends. The leg 2 in the outer edge portion thereof, near the upper end, is formed with a screw-socket 4, as shown by dotted lines in Fig. 2, and the frontv side of the upper part of the leg 1 is also provided with a screw-socket 5. The leg 1 also has an outwardly-projecting tubular socket which is litted in the center ofthe joint 4,

and in the lower edge ofthe said plate a segmental slot 1l is formed and of which the pin 9 is the center. A clamping-screw 12 projects through the slot 11 and engages the socket 5 in the leg 1 to adjust the saidleg and firmly secure it at different distances from the leg 2. The one side edge of the plate 8 near its lower edge has a rearwardly-extending right-angular ear 13, with an aperture or opening 14 therein, through which is passed a clampingscrew 15. Secured to the upper portion of the side edges of the leg 2 adjacent to the location of the ear 13 is a i'lat spring 16, which has its lower end projected or bowed outwardly-to bear against the inner side of the `said ear, and through the lower end of this spring the clamping-screw 15 also passes and engages the socket 4, which is deep enough to permit the screw 15 to have considerable adjusting movement. The function of the spring 16 is to establish a tight connection between the plate 8 and the leg 2 through the v medium of the clamping-screw 15, so that the said leg may be practically held rigid in relation to the plate to serve as a centering means, and, furthermore, said spring acts to hold the plate in proper position relatively to the upper connected ends of the legs of the compasses. This plate 8 may be used in connection with the Compasses iudependentlyof the IOO ' attachments for use the leg 1, asshown by Fig. 1, is in a plane at rightangles to the leg 2, and the rod 17 is inserted in the socket 6l and adjusted to regulate its longitudinal projection beyond the terminal of the leg 1, as may be desired. The outer end of the rod 17 and the inner end of the rod 18 are then passed through the sleeve 21 and overlapped to such extent as maybe found desirable and secured' against movement by tightening the clamping-screw 22. A pencil 23 is inserted in the sleeve 19 on the outer end of rod 18 and pusheddown until the point thereof engages the surface on which the compasses and extension attachment are adapted to be used and then rmly secured through the medium of the clamping-screw 20. The sleeve 19 isdispo'sed at an outward oblique angle in relation to the rod 18 to better arrange the pencil for defining a circle or arc and to project. the marking extremity of the pencil or other marking device at the lower end thereof with obvious advantages. The pencil or other device held by the sleeve 19 may be readilyr projected outwardly from or drawn nearer to the leg 2 by loosening the sleeve 21 and correspondingly moving the overlapped ends ofthe rods 17 and 18 or by shifting the rod 17 in the socket 15.

Theimproved device will be found exceptionally useful, and a long or short pencil can be'disposed in the socket and economy thus results in the use of the marking means employed in connection with thel improved device. The segmental plate 8 or quadrant being applied to the sides of the legs 1 and 2 instead of passing through the latter, as in ordinary forms of compasses, and being of the shape shown strengthens the compasses and can be applied in operative position or detached and carried in the pocket with much less annoyance, and the clamping-screws are 1n a much more protected position and much lessliabletobecomeloosened. Furthermore,

the plurality of adjustments resident in the com passes proper and the extension devices `provide for the formation of circles of any size and avoid the procurement and use of a is claimed'as new 'is- 1. The combination with compasses, of a quadrant-plate having a pin forming the fulcrum means for the legs of the said compasses and also provided with a segmental slot, means for securing the plate to one of the legs of the compasses, and clamping means engaging the said slot and the other leg of the compasses whereby the latter may be adj usted and held in fixed relation to the `first-mentioned leg.

2. The combination with a pair of compasses, of a spring depending from the upper portion of the outer side edge thereof, a quadrant-plate applied to the outer sides of the upper portions of the legs and having a segmental slot therein and an angular projection near the lower edge at one side, a clamping-screw passing through said slot into one of the legs, and a clamping-screw extending through the projection and the spring into the other leg.

3. The combination of a pair of compasses having means for holding the legs thereof in rigid spaced relation, one of the legs being provided with a socket and a clamping-screw, an extension-rod adj ustably mounted in the said socket, a second rod having a socket at its outer end adapted lto receive a pencil, and an elliptical sleeve to which the outer end of the first-mentioned rod and the inner end of the rod carrying the socket are passed and r adj ustably held.

In testimony whereof I affix my signature in presence of two Witnesses.

BURT E. GrOVE.`

Witnesses:

JOHN S. TEWKSBURY, EDWIN L. SLEEPER.

IOO 

